Thanks Glenn!!
My lack of literature on design concepts for the bell is making the idea risky. My application is so niche I'm concerned to be designing myself without an expert on hand(any volunteers?

. I also don't have much time to come up with a different plan. I have 2 55 gal drums. Can I use one for the rmh and pipe it directly to a second "settling" barrel, that is barely nudged into the baby barn, and then exhaust the remaining heat through a short bench to finish exhaust out near the first barrel?
Do you have a suggestion for resources?
Should the second barrel have input in top and cool down (exhaust) near base? Does 8" pipe still work? How do I even work this mathematically? I am a business so the pressure, of performance, is on! I feel confident in being capable of cutting a circle in the barrel and using metal heat "cement" for sealing the input/output of the second barrel. I do see the reasoning for your suggestion and am just hesitant due to more unknowns.
The heat barn is going to be VERY insulated and lined with reflective material. The only airflow to and from the heat barn will be when the door is open and when the vents, that we connect the barns to are open.(we were planing on cutting those as we got a feel for output of heat and how responsive each barn is.
Another note: I will use cinder blocks spaced 6" apart as base for the pallet, used as floor for heat barn. These pallets were used in commercial HVAC unit transportation and are rated for 10,000 lbs.
I would be willing to spend a little money on a custom design or a proven concept. Although, our budget will never have enough room for the invaluable information I feel I've already learned!! Your experiences are priceless! I enjoy this adventure and can't wait to find a solution for our quail barn!
Thanks!
Nicole